Inhibition of MMP-2 secretion from brain tumor cells suggests chemopreventive properties of a furanocoumarin glycoside and of chalcones isolated from the twigs of Dorstenia turbinata

Significance of Chalcone Scaffolds in Medicinal Chemistry

Chalcone is a simple naturally occurring α,β-unsaturated ketone with biological importance, which can also be easily synthesized in laboratories by reaction between two aromatic scaffolds. In plants, chalcones occur as polyphenolic compounds of different frameworks which are bioactive molecules that have been in traditional medicinal practice for many years. Chalcone-based lead molecules have been developed, possessing varied potentials such as antimicrobial, antiviral, anti-inflammatory, anticancer, anti-oxidant, antidiabetic, antihyperurecemic, and anti-ulcer effects. Chalcones contribute considerable fragments to give important heterocyclic molecules with therapeutic utilities targeting various diseases. These characteristic features have made chalcone a topic of interest among researchers and have attracted investigations into this widely applicable structure. This review highlights the extensive exploration carried out on the synthesis, biotransformations, chemical reactions, hybridization, and pharmacological potentials of chalcones, and aims to provide an extensive, thorough, and critical review of their importance, with emphasis on their properties, chemistry, and biomedical applications to boost future investigations into this potential scaffold in medicinal chemistry.

Isolation and biological activity of natural chalcones based on antibacterial mechanism classification

Bacterial infection, which is still one of the leading causes of death in humans, poses an enormous threat to the worldwide public health system. Antibiotics are the primary medications used to treat bacterial diseases. Currently, the discovery of antibiotics has reached an impasse, and due to the abuse of antibiotics resulting in bacterial antibiotic resistance, researchers have a critical desire to develop new antibacterial agents in order to combat the deteriorating antibacterial situation. Natural chalcones, the flavonoids consisting of two phenolic rings and a three-carbon α, β-unsaturated carbonyl system, possess a variety of biological and pharmacological properties, including anti-cancer, anti-inflammatory, antibacterial, and so on. Due to their potent antibacterial properties, natural chalcones possess the potential to become a new treatment for infectious diseases that circumvents existing antibiotic resistance. Currently, the majority of research on natural chalcones focuses on their synthesis, biological and pharmacological activities, etc. A few studies have been conducted on their antibacterial activity and mechanism. Therefore, this review focuses on the antibacterial activity and mechanisms of seventeen natural chalcones. Firstly, seventeen natural chalcones have been classified based on differences in antibacterial mechanisms. Secondly, a summary of the isolation and biological activity of seventeen natural chalcones was provided, with a focus on their antibacterial activity. Thirdly, the antibacterial mechanisms of natural chalcones were summarized, including those that act on bacterial cell membranes, biological macromolecules, biofilms, and quorum sensing systems. This review aims to lay the groundwork for the discovery of novel antibacterial agents based on chalcones.

Umbelliferon: a review of its pharmacology, toxicity and pharmacokinetics

Coumarin, a plant secondary metabolite, has various pharmacological activities, including antioxidant stress and anti-inflammatory effects. Umbelliferone, a common coumarin compound found in almost all higher plants, has been extensively studied for its pharmacological effects in different disease models and doses with complex action mechanisms. This review aims to summarize these studies and provide useful information to relevant scholars. The pharmacological studies demonstrate that umbelliferone has diverse effects such as anti-diabetes, anti-cancer, anti-infection, anti-rheumatoid arthritis, neuroprotection, and improvement of liver, kidney, and myocardial tissue damage. The action mechanisms of umbelliferone include inhibition of oxidative stress, inflammation, and apoptosis, improvement of insulin resistance, myocardial hypertrophy, and tissue fibrosis, in addition to regulation of blood glucose and lipid metabolism. Among the action mechanisms, the inhibition of oxidative stress and inflammation is the most critical. In short, these pharmacological studies disclose that umbelliferone is expected to treat many diseases, and more research should be conducted.

Chalcones: Promising therapeutic agents targeting key players and signaling pathways regulating the hallmarks of cancer

The need for innovative anticancer treatments with high effectiveness and low toxicity is urgent due to the development of malignancies that are resistant to chemotherapeutic agents and the poor specificity of existing anticancer treatments. Chalcones are 1,3-diaryl-2-propen-1-ones, which are the precursors for flavonoids and isoflavonoids. Chalcones are readily available from a wide range of natural resources and consist of very basic chemical scaffolds. Because the ease with which the synthesis it allows for the production of several chalcone derivatives. Various in-vitro and in-vivo studies indicate that naturally occurring and synthetic chalcone derivatives exhibit promising biological activities against cancer hallmarks such as proliferation, angiogenesis, invasion, metastasis, inflammation, stemness, and regulation of cancer epigenetics. According to their structure and functional groups, chalcones derivatives and their hybrid compounds exert a broad range of biological activities through targeting key elements and signaling molecules relevant to cancer progression. This review will provide valuable insights into the latest updates of chalcone groups as anticancer agents and extensively discuss their underlying molecular mechanisms of action.

Licorice (Glycyrrhiza glabra L.)-Derived Phytochemicals Target Multiple Signaling Pathways to Confer Oncopreventive and Oncotherapeutic Effects

Cancer is a highly lethal disease, and its incidence has rapidly increased worldwide over the past few decades. Although chemotherapeutics and surgery are widely used in clinical settings, they are often insufficient to provide the cure for cancer patients. Hence, more effective treatment options are highly needed. Although licorice has been used as a medicinal herb since ancient times, the knowledge about molecular mechanisms behind its diverse bioactivities is still rather new. In this review article, different anticancer properties (antiproliferative, antiangiogenic, antimetastatic, antioxidant, and anti-inflammatory effects) of various bioactive constituents of licorice (Glycyrrhiza glabra L.) are thoroughly described. Multiple licorice constituents have been shown to bind to and inhibit the activities of various cellular targets, including B-cell lymphoma 2, cyclin-dependent kinase 2, phosphatidylinositol 3-kinase, c-Jun N-terminal kinases, mammalian target of rapamycin, nuclear factor-κB, signal transducer and activator of transcription 3, vascular endothelial growth factor, and matrix metalloproteinase-3, resulting in reduced carcinogenesis in several in vitro and in vivo models with no evident toxicity. Emerging evidence is bringing forth licorice as an anticancer agent as well as bottlenecks in its potential clinical application. It is expected that overcoming toxicity-related obstacles by using novel nanotechnological methods might importantly facilitate the use of anticancer properties of licorice-derived phytochemicals in the future. Therefore, anticancer studies with licorice components must be continued. Overall, licorice could be a natural alternative to the present medication for eradicating new emergent illnesses while having just minor side effects.

Antioxidant, Antimicrobial, Cytotoxicity, and Larvicidal Activities of Selected Synthetic Bis-Chalcones

Plants are known to have numerous phytochemicals and other secondary metabolites with numerous pharmacological and biological properties. Among the various compounds, polyphenols, flavonoids, anthocyanins, alkaloids, and terpenoids are the predominant ones that have been explored for their biological potential. Among these, chalcones and bis-chalcones are less explored for their biological potential under in vitro experiments, cell culture models, and animal studies. In the present study, we evaluated six synthetic bis-chalcones that were different in terms of their aromatic cores, functional group substitution, and position of substitutions. The results indicated a strong antioxidant property in terms of DPPH and ABTS radical-scavenging potentials and ferric-reducing properties. In addition, compounds 1, 2, and 4 exhibited strong antibacterial activities against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Salmonella enteritidis. The disc diffusion assay values were indicative of the antibacterial properties of these compounds. Overall, the study indicated the antioxidant and antimicrobial properties of the compounds. Our preliminary studies point to the potential of this class of compounds for further in vivo investigation.

Medicinal Potential of Heterocyclic Compounds from Diverse Natural Sources for the Management of Cancer

Natural products form a significant portion of medicinal agents that are currently used for the management of cancer. All these natural products have unique structures along with diverse action mechanisms with the capacity to interact with different therapeutic targets of several complex disorders. Although plants contribute as a major source of natural products with anti-cancer potential, the marine environment and microbes have also bestowed some substantial chemotherapeutic agents. A few examples of anti-cancer agents of natural origin include vincristine, vinblastine, paclitaxel, camptothecin and topotecan obtained from plants, bryostatins, sarcodictyin and cytarabine from marine organisms and bleomycin and doxorubicin from micro-organisms (dactinomycin, bleomycin and doxorubicin). The incredible diversity in the chemical structures and biological properties of compounds obtained from million species of plants, marine organisms and microorganisms present in nature has commenced a new era of potential therapeutic anti-cancer agents.

Natural Chalcones in Chinese Materia Medica: Licorice

Licorice is an important Chinese materia medica frequently used in clinical practice, which contains more than 20 triterpenoids and 300 flavonoids. Chalcone, one of the major classes of flavonoid, has a variety of biological activities and is widely distributed in nature. To date, about 42 chalcones have been isolated and identified from licorice. These chalcones play a pivotal role when licorice exerts its pharmacological effects. According to the research reports, these compounds have a wide range of biological activities, containing anticancer, anti-inflammatory, antimicrobial, antioxidative, antiviral, antidiabetic, antidepressive, hepatoprotective activities, and so on. This review aims to summarize structures and biological activities of chalcones from licorice. We hope that this work can provide a theoretical basis for the further studies of chalcones from licorice.

Highly selective anthraquinone-chalcone hybrids as potential antileukemia agents

A series of 23 novel anthraquinone-chalcone hybrids containing amide function was synthesized and structurally characterized. Sixteen compounds exerted strong cytotoxic activities against K562, Jurkat and HL-60 leukemia cell lines and significantly lower cytotoxic effects against normal MRC-5 cells, indicating very high selectivity in their anticancer action. The compounds 6g, 6u and 6v activate apoptosis in K562 cells through the extrinsic and intrinsic apoptotic pathway. The compound 6e triggered apoptosis in K562 cells only through the extrinsic apoptotic pathway. Treatment of K562 cells with each of these four compounds caused decrease in the expression levels of MMP2, MMP9, and VEGF, suggesting their anti-invasive, antimetastatic and antiangiogenic properties. The compounds 6g and 6v downregulated expression levels of miR-155 in K562 cells, while compounds 6e and 6u upregulated miR-155 levels in treated cells, in comparison with control cells. The structure-based 3-D QSAR models for 6f, 6e, 6i and 6l describe pro-apoptotic activity against caspase-3.

Anti-Inflammatory Pyranochalcone Derivative Attenuates LPS-Induced Acute Kidney Injury via Inhibiting TLR4/NF-κB Pathway

Treatment of septic acute kidney injury (AKI) has still been beyond satisfaction, although anti-inflammatory therapy is beneficial for sepsis-induced AKI. Compound 5b was derived from natural pyranochalcones and exhibited potent anti-inflammatory activity in adjuvant-induced arthritis. In this study, we aimed to investigate the renoprotective effects and potential mechanism of 5b against lipopolysaccharide (LPS)-induced AKI. C57BL/6 mice and human renal proximal tubule cell line (HK-2 cell) were treated with LPS, respectively. Compound 5b was orally administrated at a dose of 25 mg/kg/day for 5 days before LPS (10 mg/kg) intraperitoneal injection. Cells were pretreated with 25 μg/mL 5b for 30 min before LPS (1 μg/mL) treatment. Pretreatment with 5b markedly alleviated tubular injury and renal dysfunction in LPS-induced AKI. The expression of IL-1β, IL-6, and TNF-α both in renal tissue of AKI mice and in the LPS-stimulated HK-2 cell culture medium were reduced by 5b treatment (p < 0.05). The results of immunohistochemistry staining showed that 5b reduced the expression of NF-κB p65 in kidneys. Similarly, 5b decreased the LPS-induced levels of NF-κB p65 and TLR4 proteins in kidneys and HK-2 cells. These data demonstrated that a potent pyranochalcone derivative, 5b, exhibited renoprotective effect against LPS-induced AKI, which was associated with anti-inflammatory activity by inhibiting the TLR4/NF-κB pathway.

Design, synthesis and cytotoxicity evaluation of novel (E)-3-(3-aryl-1-phenyl-1H-pyrazol-4-yl)-1-(pyridin-3-yl)prop-2-en-1-ones as anticancer agents

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Multi-spectroscopic and molecular modeling investigation of the interactions between prantschimgin and matrix metalloproteinase 9 (MMP9)

The binding of prantschimgin (PRAN) to matrix metalloproteinase 9 (MMP9) was investigated using multiple techniques. Fluorescence spectroscopy showed that PRAN could quench the MMP9 fluorescence spectra. Changes in the UV/vis and Fourier transform infrared (FTIR) spectra were observed upon ligand binding, along with a significant degree of tryptophan fluorescence quenching on complex formation. The interaction of PRAN with MMP9 has also been studied using molecular docking and molecular dynamics (MD) simulation. The binding models demonstrated aspects of PRAN's conformation, active site interaction, important amino acids and hydrogen bonding. Computational mapping of the possible binding site of PRAN revealed that the ligand is bound in a large hydrophobic cavity of MMP9. The MD simulation results suggested that this ligand can interact with the protein, with little affecting the secondary structure. The results not only lead to a better understanding of interactions between PRAN and MMP9, but also provide useful data about the influence of PRAN on the structural conformation. The data provided in this study will be useful for designing a new agonist of MMP9 with the desired activity.

Protective Effects of Dihydrocaffeic Acid, a Coffee Component Metabolite, on a Focal Cerebral Ischemia Rat Model

We recently reported the protective effects of chlorogenic acid (CGA) in a transient middle cerebral artery occlusion (tMCAo) rat model. The current study further investigated the protective effects of the metabolites of CGA and dihydrocaffeic acid (DHCA) was selected for further study after screening using the same tMCAo rat model. In the current study, tMCAo rats (2 h of MCAo followed by 22 h of reperfusion) were injected with various doses of DHCA at 0 and 2 h after onset of ischemia. We assessed brain damage, functional deficits, brain edema, and blood-brain barrier damage at 24 h after ischemia. For investigating the mechanism, in vitro zymography and western blotting analysis were performed to determine the expression and activation of matrix metalloproteinase (MMP)-2 and -9. DHCA (3, 10, and 30 mg/kg, i.p.) dose-dependently reduced brain infarct volume, behavioral deficits, brain water content, and Evans Blue (EB) leakage. DHCA inhibited expression and activation of MMP-2 and MMP-9. Therefore, DHCA might be one of the important metabolites of CGA and of natural products, including coffee, with protective effects on ischemia-induced neuronal damage and brain edema.

Anti-cancer chalcones: Structural and molecular target perspectives

Chalcone or (E)-1,3-diphenyl-2-propene-1-one scaffold remained a fascination among researchers in the 21st century due to its simple chemistry, ease of synthesis and a wide variety of promising biological activities. Several natural and (semi) synthetic chalcones have shown anti-cancer activity due to their inhibitory potential against various targets namely ABCG2/P-gp/BCRP, 5α-reductase, aromatase, 17-β-hydroxysteroid dehydrogenase, HDAC/Situin-1, proteasome, VEGF, VEGFR-2 kinase, MMP-2/9, JAK/STAT signaling pathways, CDC25B, tubulin, cathepsin-K, topoisomerase-II, Wnt, NF-κB, B-Raf and mTOR etc. In this review, a comprehensive study on molecular targets/pathways involved in carcinogenesis, mechanism of actions (MOAs), structure activity relationships (SARs) and patents granted have been highlighted. With the knowledge of molecular targets, structural insights and SARs, this review may be helpful for (medicinal) chemists to design more potent, safe, selective and cost effective anti-cancer chalcones.

Effects of psoralens as anti-tumoral agents in breast cancer cells

This review examines the biological properties of coumarins, widely distributed at the highest levels in the fruit, followed by the roots, stems and leaves, by considering their beneficial effects in the prevention of some diseases and as anti-cancer agents. These compounds are well known photosensitizing drugs which have been used as pharmaceuticals for a broad number of therapeutic applications requiring cell division inhibitors. Despite this, even in the absence of ultraviolet rays they are active. The current paper mainly focuses on the effects of psoralens on human breast cancer as they are able to influence many aspects of cell behavior, such as cell growth, survival and apoptosis. In addition, analytical and pharmacological data have demonstrated that psoralens antagonize some metabolizing enzymes, affect estrogen receptor stability and counteract cell invasiveness as well as cancer drug resistance. The scientific findings summarized highlight the pleiotropic functions of phytochemical drugs, given that recently their target signals and how these are modified in the cells have been identified. The encouraging results in this field suggest that multiple modulating strategies based on coumarin drugs in combination with canonical chemotherapeutic agents or radiotherapy could be a useful approach to address the treatment of many types of cancer.

A hybrid approach to new molecular scaffolds

Our various efforts toward the synthesis of a set of novel sugar hybrid scaffolds of several biologically active natural products such as taxol, steroids, β-lactams, and otteliones are presented. We have shown the application of the hybrid approach to design and rapidly generate a library of novel natural product-like compounds, which may have interesting biological features, using metathesis and/or cycloaddition reactions as key steps.

An update on antitumor activity of naturally occurring chalcones

Chalcones, which have characteristic 1,3-diaryl-2-propen-1-one skeleton, are mainly produced in roots, rhizomes, heartwood, leaves, and seeds of genera Angelica, Sophora, Glycyrrhiza, Humulus, Scutellaria, Parartocarpus, Ficus, Dorstenia, Morus, Artocarpus, and so forth. They have become of interest in the research and development of natural antitumor agents over the past decades due to their broad range of mechanisms including anti-initiation, induction of apoptosis, antiproliferation, antimetastasis, antiangiogenesis, and so forth. This review summarizes the studies on the antitumor activity of naturally occurring chalcones and their underlying mechanisms in detail during the past decades.

Triterpene esters: natural products from Dorstenia arifolia (Moraceae)

The phytochemical study of Dorstenia arifolia Lam. (Moraceae) has led to the identification of 18 triterpenes esterified by fatty acids, five triterpenes without esterification, 12 triterpenes esterified by acetic acid, together with a known furanocoumarin: α-amyrin (1), β-amyrin (2) α-amyrin acetate (3) β-amyrin acetate (4), α-amyrin octanoate (5), β-amyrin octanoate (6), α-amyrin decanoate (7), β-amyrin decanoate (8), α-amyrin dodecanoate (9), β-amyrin dodecanoate (10), α-amyrin tetradecanoate (11), β-amyrin tetradecanoate (12), α-amyrin hexadecanoate (13), β-amyrin hexadecanoate (14), glutinol (15), glutinyl acetate (16), 11-oxo-α-amyrin (17), 11-oxo-β-amyrin (18), 11-oxo-α-amyrin acetate (19), 11-oxo-β-amyrin acetate (20) 11-oxo-α-amyrin octanoate (21) 11-oxo-β-amyrin octanoate (22), 11-oxo-α-amyrin decanoate (23), 11-oxo-β-amyrin decanoate (24) 11-oxo-α-amyrin dodecanoate (25) 11-oxo-β-amyrin dodecanoate (26), ursa-9(11),12-dien-3-yl acetate (27), oleana-9(11),12-dien-3-yl acetate (28), ursa-9(11),12-dien-3-yl decanoate (29), oleana-9(11),12-dien-3-yl decanoate (30), 12,13-epoxyolean-3-yl acetate (31), 12,13-epoxyolean-9(11)en-3-yl acetate (32), taraxeryl acetate (33), lupenyl acetate (34), lanosta-8,24-dien-3-yl acetate (35) and psoralen (36). The identification of the triterpene compounds isolated as isomeric mixtures obtained from the hexane extract was based mainly in mass spectra and ¹³C-NMR data. The long-chain alkanoic acid esters of the triterpenes α- and β-amyrin; 11-oxo-α- and 11-oxo-β-amyrin; ursa- and olean-9(11),12-dien-3-yl; have not been reported before in the literature as constituents of the Dorstenia genus.

2-Hydroxychalcone and xanthohumol inhibit invasion of triple negative breast cancer cells

Breast cancer is estimated as one of the most common causes of cancer death among women. In particular, triple negative breast cancers (TNBCs), which do not express the genes for estrogen/progesterone receptors (ER/PR) and human epidermal growth factor receptor 2 (HER2), have been associated with poor prognosis and metastasis. Chalcones, the biosynthetic precursors of flavonoids present in edible plants, exert cytotoxic and chemopreventive activities. Although mounting evidence suggests the anticancer properties of chalcones, limited information is available regarding the inhibitory effects of chalcones on the aggressiveness of breast cancer cells. The present study aimed to investigate the effects of chalcone and its derivatives on the growth and the invasiveness of TNBC cells. Here, we showed that treatment with chalcone, 2-hydroxychalcone, and xanthohumol for 24h inhibited the growth of MDA-MB-231 cells with IC50 values of 18.1, 4.6, and 6.7 μM, respectively. Similarly, Chalcone, 2-hydroxychalcone, and xanthohumol also exerted cytotoxicity in another TNBC cell line, Hs578T. Neohesperidin dihydrochalcone, 4-methoxychalcone, and hesperidin methylchalcone did not show the cytotoxicity on the MDA-MB-231 cells. Xanthohumol and 2-hydroxychalcone induced apoptosis by Bcl-2 downregulation. Importantly, 2-hydroxychalcone and xanthohumol exerted more potent inhibitory effects on the proliferation, MMP-9 expression and invasive phenotype of MDA-MB-231 than chalcone. These results suggest a potential application of these chalcones as anticancer agents that can alleviate malignant progression of TNBC.

Palladium-catalyzed, pyrrolidine-mediated arylmethylation of ketones and aldehydes with coumarinyl(methyl) acetates

We report the palladium-catalyzed, pyrrolidine-mediated α-benzylation of enamines generated from aldehydes and ketones. The method allows for direct coupling of medicinally relevant coumarin moieties with aldehydes and ketones in good yield under mild conditions. The reaction is believed to proceed via a Pd-π-benzyl complex generated from (coumarinyl)methyl acetates.

Chlorogenic acid ameliorates brain damage and edema by inhibiting matrix metalloproteinase-2 and 9 in a rat model of focal cerebral ischemia

Chlorogenic acid (CGA) has been reported to have various beneficial effects on the cardiovascular and central nervous systems. The purpose of the current study was to investigate whether CGA has protective effects against cerebral ischemia and whether these effects are due to modification of brain edema-related vascular factors. In a rat model of transient middle cerebral artery occlusion (MCAo, 2h of occlusion followed by 22 h of reperfusion), we measured infarct volume and performed behavioral test to evaluate the effects of CGA on brain damage and sensory-motor functional deficits. Brain water content and Evans blue extravasation were measured to evaluate brain edema and blood brain barrier (BBB) damage. Lipid peroxidation (LPO) and the expressions and activities of matrix metalloproteinase (MMP)-2 and MMP-9 were measured to investigate the mechanisms of action. Intraperitoneal injection of CGA (3, 10, and 30 mg/kg) at 0 h and 2h after MCAo dose-dependently reduced infarct volume and sensory-motor functional deficits. It also reduced brain water content and Evans blue extravasation. Mechanistically, CGA reduced LPO and MMPs expressions and activities. These results suggest that CGA reduces brain damage, BBB damage and brain edema by radical scavenging activity and the inhibitory effects on MMP-2 and MMP-9.

Furanocoumarins from Dorstenia foetida

The linear furanocoumarins 5-(2,3-epoxy-3-methyl-butoxy)-chalepensin, 5-methoxy-3-(3-methyl-2,3-dihydroxybutyl)-psoralen-diacetate (7), 5-methoxy-3-[3-(β-D-glucopyranosyloxy)-2-acetyloxy-3-methyl-butyl]-psoralen and 5-(3-methyl-2,3-dihydroxybutyloxy)-3-[3-(β-D-glucopyranosyloxy)-2-hydroxy-3-methyl-butyl]-psoralen, and the coumarin derivative 7-hydroxy-5-methoxy-6-carboxymethyl-3-[3-(β-D-glucopyranosyloxy)-2-hydroxy-3-methyl-butyl]-coumarin were isolated from the leaves of Dorstenia foetida (Moraceae) along with the known compounds psoralen, bergapten, isopimpinellin, phellopterin, 5-methoxychalepensin and turbinatocoumarin. Further furanocoumarins were characterized by ESI-MS/MS investigations. The nonpolar extracts of D. foetida exhibit antifungal, antibacterial and cytotoxic activity, however, no anthelminthic activity.

Suppression of phorbol-12-myristate-13-acetate-induced tumor cell invasion by piperine via the inhibition of PKCα/ERK1/2-dependent matrix metalloproteinase-9 expression

Piperine is a major component of black pepper, Piper nigrum Linn, used widely in traditional medicine. Several previous studies reported that piperine possesses various beneficial biological activities including antioxidant, anti-tumor and anti-inflammation properties. In the present study, we investigated the inhibitory effects of piperine on tumor invasion and migration and the possible mechanisms involved using human fibrosarcoma HT-1080 cells. We found that piperine suppresses PMA-enhanced matrix metalloproteinase-9 (MMP-9) expression at the protein, mRNA, and transcriptional levels through the suppression of NF-κB and AP-1 activation without changing the level of tissue inhibitor of metalloproteinase (TIMP)-1. Piperine also inhibits PMA-enhanced membrane-type 1 MMP expression without changing the level of tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2. Piperine inhibited PMA-induced NF-κB and c-Jun nuclear translocation, which are upstream of PMA-induced MMP-9 expression and invasion. Furthermore, piperine strongly repressed the PMA-induced phosphorylation of ERK, which are dependent on the PKCα pathway. In conclusion, we demonstrated that the anti-invasive effects of piperine may occur through inhibition of PKCα and ERK phosphorylation and reduction of NF-κB and AP-1 activation, leading to down-regulation of MMP-9 expression. Thus, piperine has potential as a potent anti-cancer drug in therapeutic strategies for fibrosarcoma metastasis.

The role of chalcones in suppression of NF-κB-mediated inflammation and cancer

Although consumption of fruits, vegetables, spices, cereals and pulses has been associated with lower incidence of cancer and other chronic diseases, how these dietary agents and their active ingredients minimize these diseases, is not fully understood. Whether it is oranges, kawa, hops, water-lilly, locorice, wax apple or mulberry, they are all connected by a group of aromatic ketones, called chalcones (1,3-diaryl-2-propen-1-ones). Some of the most significant chalcones identified from these plants include flavokawin, butein, xanthoangelol, 4-hydroxyderricin, cardamonin, 2',4'-dihydroxychalcone, isoliquiritigenin, isosalipurposide, and naringenin chalcone. These chalcones have been linked with immunomodulation, antibacterial, antifungal, antiviral, anti-inflammatory, antioxidant, anticancer, and antidiabetic activities. The current review, however, deals with the role of various chalcones in inflammation that controls both the immune system and tumorigenesis. Inflammatory pathways have been shown to mediate the survival, proliferation, invasion, angiogenesis and metastasis of tumors. How these chalcones modulate inflammatory pathways, tumorigenesis and immune system is the focus of this review.

Suppression of phorbol-12-myristate-13-acetate-induced tumor cell invasion by bergamottin via the inhibition of protein kinase Cdelta/p38 mitogen-activated protein kinase and JNK/nuclear factor-kappaB-dependent matrix metalloproteinase-9 expression

Matrix metalloproteinase (MMP) plays an important role in the invasion and metastasis of cancer cells. The inhibitory effects of bergamottin, a cytochrome P450 inhibitor from Citrus paradis (grapefruit), on tumor invasion and migration and the possible mechanisms involved in this inhibition were investigated in human fibrosarcoma HT-1080 cells. Bergamottin reduced phorbol-12-myristate-13-acetate (PMA)-induced activation of MMP-9 and MMP-2 and further inhibited cell invasion and migration. Bergamottin suppressed PMA-enhanced expression of MMP-9 protein, mRNA and transcription activity levels through suppression of nuclear factor-kappaB (NF-kappaB) activation without changing the tissue inhibitor of metalloproteinase 1 level. Bergamottin also reduced PMA-enhanced MMP-2 expression through suppression of membrane-type 1 MMP, but did not alter tissue inhibitor of metalloproteinase 2 levels. Bergamottin inhibited PMA-induced NF-kappaB nuclear translocation and IkappaBalpha degradation, which are upstream of PMA-induced MMP-9 expression and invasion. Furthermore, bergamottin strongly repressed the PMA-induced phosphorylation of p38 mitogen-activated protein kinase and c-Jun N-terminal kinase (JNK), which are dependent on the protein kinase C-delta pathway. In conclusion, we demonstrated that the anti-invasive effects of bergamottin might occur through inhibition of protein kinase C-delta, p38 mitogen-activated protein kinase, and JNK phosphorylation and reduction of NF-kappaB activation, leading to downregulation of MMP-9 expression. These results suggest that the suppression of MMP expression contributes, at least in part, to the antitumor activity of bergamottin.

Cameroonian medicinal plants: pharmacology and derived natural products

Many developing countries including Cameroon have mortality patterns that reflect high levels of infectious diseases and the risk of death during pregnancy and childbirth, in addition to cancers, cardiovascular diseases and chronic respiratory diseases that account for most deaths in the developed world. Several medicinal plants are used traditionally for their treatment. In this review, plants used in Cameroonian traditional medicine with evidence for the activities of their crude extracts and/or derived products have been discussed. A considerable number of plant extracts and isolated compounds possess significant antimicrobial, anti-parasitic including antimalarial, anti-proliferative, anti-inflammatory, anti-diabetes, and antioxidant effects. Most of the biologically active compounds belong to terpenoids, phenolics, and alkaloids. Terpenoids from Cameroonian plants showed best activities as anti-parasitic, but rather poor antimicrobial effects. The best antimicrobial, anti-proliferative, and antioxidant compounds were phenolics. In conclusion, many medicinal plants traditionally used in Cameroon to treat various ailments displayed good activities in vitro. This explains the endeavor of Cameroonian research institutes in drug discovery from indigenous medicinal plants. However, much work is still to be done to standardize methodologies and to study the mechanisms of action of isolated natural products.

Mild decarboxylative allylation of coumarins

Allyl esters of 3-carboxylcoumarins undergo facile decarboxylative coupling at just 25-50 degrees C. This represents the first extension of decarboxylative C-C bond-forming reactions to the coupling of aromatics with sp(3)-hybridized electrophiles. Finally, the same concept can be applied to the sp(2)-sp(3) couplings of pyrones and flavones. Thus, a variety of biologically important heteroaromatics can be readily functionalized without the need for strong bases or stoichiometric organometallics that are typically required for more standard cross-coupling reactions.

A New Synthetic Route of 2-Aroyl- and 2-Benzyl-Benzofurans and their Application in the Total Synthesis of a Metabolite Isolated from Dorstenia gigas

The Lewis acid-catalyzed cyclization of the (Z)-3-(dimethylamino)-2-aryloxy-1-arylprop-2-en-1-ones 4a–h leads to a regioselective and short synthesis of 2-aroylbenzofurans 2a–h. The Wolff–Kishner reduction of the latter yielded a series of substituted 2-benzylbenzofurans 3a–h. This methodology was applied in the first total synthesis of the metabolite 2-(4-hydroxybenzyl)-6-methoxybenzofuran 1, which was isolated from the tropical plant Dorstenia gigas, and obtained through a six-step route and in a 24% overall yield.

Comparison of plants used for skin and stomach problems in Trinidad and Tobago with Asian ethnomedicine

This paper provides a preliminary evaluation of fifty-eight ethnomedicinal plants used in Trinidad and Tobago for skin problems, stomach problems, pain and internal parasites for safety and possible efficacy. Thirty respondents, ten of whom were male were interviewed from September 1996 to September 2000 on medicinal plant use for health problems. The respondents were obtained by snowball sampling, and were found in thirteen different sites, 12 in Trinidad and one in Tobago. The uses are compared to those current in Asia. Bambusa vulgaris, Bidens alba, Jatropha curcas, Neurolaena lobata, Peperomia rotundifolia and Phyllanthus urinaria are possibly efficacious for stomach problems, pain and internal parasites. Further scientific study of these plants is warranted.